The present invention relates to avionics. Modern commercial/private aircraft, as well as older aircraft, generally include a myriad of instrumentation panels associated with electronic devices having controls, displays, and software applications, which are used to present information to pilots and/or copilots during flight. The electronic devices, controls, displays and applications are interfaced together to form avionics equipment within the aircraft. Pilots (where “pilot” includes copilots and any other controller of the aircraft) access one or more interface devices of the avionics equipment prior to and during the flight. Some of this information presented monitors the status of equipment on the aircraft, while other switches and knobs are used to control functions of the aircraft such as throttles (engine speed), switches (lights, radios, etc), levers (landing gear and flaps), and controls for navigation, for example.
Pilots currently manually check for the proper operation of the magnetos on a piston-powered aircraft. An aircraft typically has two magnetos for redundancy, referred to as the left magneto and the right magneto. The magneto generates the spark which ignites the fuel in the combustion chamber. To check for proper operation of the magnetos, the pilot performs a “run up” where the RPM of the engine is increased to something slightly below normal cruise RPM while the pilot holds the brakes. A run up is usually performed while the aircraft is on the ground and prior to takeoff.
During the run up, the pilot disables one of the magnetos to check the proper operation of the other magneto. To do this, the pilot typically uses a four-position rotary switch labeled: Off-R-L-Both. The Off position disables both magnetos, e.g., by shorting the spark-generating circuit so that the magneto cannot generate a spark. The L position enables the left magneto by shorting only the right magneto. The R position enables the right magneto by shorting only the left magneto. The Both position enables both magnetos to operate and does not short either of the magnetos. The Both position is used for normal operation.
When a magneto is shorted, the RPM of the engine drops because the engine is only running on one magneto. The current method for checking the magnetos is to run the engine with the switch in the Both position and increase the engine RPM to a value approximately between cruise and idle. When the engine RPM has stabilized, the pilot moves the switch to the R position and watches the RPM drop on the tachometer. The pilot then moves the switch back to the both position and waits for the RPM to rise and stabilize. The pilot then moves the switch to the L position and again watches the RPM drop. In order to pass the magneto check, the RPM drop for each test, as well as the difference between the RPM drop for each side must be within the specifications published by the engine manufacturer.
Because the engine will run with only one magneto operating, it is possible for pilots to unintentionally leave the switch in either the L or R position during engine start, takeoff and flight. This is unsafe because if the operating magneto fails, the other magneto is not operating because it is shorted. Such a situation causes a complete engine failure.
Other U.S. patents of interest relative to this disclosure include the following, each of which is incorporated herein by reference: U.S. Pat. No. 4,127,847 “Monitoring system for aircraft master switch”; U.S. Pat. No. 4,243,970 “Open circuit alarm”; and U.S. Pat. No. 5,353,657 “Airplane engine starter system and housing”.
Accordingly, there is a need for methods and systems that facilitate evaluation of magneto operation while reducing pilot workload and potential for error.